Poj 3461 Oulipo

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**oulipo**the French author Georges Perec (1936–1982) once wrote a book, La disparition,without  theLetter ' E '. He was a member of  theOulipo Group. AQuote  from  theBook:tout avait Pair normal, mais Tout s ' affirmait faux. Tout avait Fair normal, d ' Abord, puis surgissait l ' inhumain, l ' affolant. Il aurait voulu savoir oùs ' articulait l ' association qui l ' unissait au roman:stir son tapis, Assaillantàtout instant s On imagination, l ' intuition d ' un tabou, la vision d ' un mal obscur, d ' un quoi vacant, d ' UN non-dit:la vision, l ' avision D ' Un oubli commandant tout, oùs ' abolissait la raison:tout avait l ' air normal mais ... Perec would probably has scored high (orrather, low)inch  theFollowing contest. People is asked to WriteA perhaps even meaningfultext  on someSubject with  asFew occurrences ofAgiven“Word” asPossible. Our task is  toProvide theJury withA program thatCounts these occurrences,inchOrder toObtain a ranking of  theCompetitors. These competitors oftenWriteVery long texts withNonsense meaning; A sequence of  -, theConsecutive ' T ' s is  notUnusual. And they never use spaces. So we want toQuickly find out how often aWord, i.e., agiven string, occursinchAtext. More formally:given  theAlphabet {' A ', ' B ', ' C ', ..., ' Z '} andFinite strings Over  thatAlphabet, aWordW andAtextTCount  the  Number  ofOccurrences ofWinchT. All theConsecutivecharacters  ofW must exactly match consecutivecharacters  ofT. Occurrences may overlap. Inputthe FirstLine of  theInputfile containsA single Number: the  Number  ofTest Cases toFollow. Each test case has theFollowing Format:one line with  the WordW, astring  Over{' A ', ' B ', ' C ', ..., ' Z '}, with 1≤| w| ≤Ten, the(Here | w| Denotes the length  of  the stringW). One line with  the textT, astring  Over{' A ', ' B ', ' C ', ..., ' Z '}, with| w| ≤| T| ≤1, the,.OutputforeveryTest caseinch  theInputfile, theOutput shouldcontainA single Number, onA single line: the  Number  ofOccurrences of  the WordWinch  the textT.sample Input3Bapcbapcazaazazazaverdiaverdxivyerdiansample Output130

The main topic: is to give you a substring p and a main string s, how many substrings in the primary string ....
Problem-solving ideas: These days have been in the whole AC automata, just start a look reflex I think is AC automata, the result is not, because, AC automata are to you a lot of strings, let you look for the prefix, this is not, this is 22 compared so is obviously KMP, the result is ok .... But at first, I made a mistake, and I'll give you an introduction later.

On the code:

Here is the AC code:

#include <iostream>#include <cstdio>#include <cstring>using namespace STD;Const intMAXN =1000005;CharS[MAXN], P[MAXN];intNEXT[MAXN];intans;voidGetnext () {intj =0;intK =-1; next[0] = -1;intPlen =strlen(P); while(J < Plen) {if(k==-1||            P[j]==p[k]) {k++;            j + +;        NEXT[J] = k; }Elsek = Next[k]; }}intKMP () {inti =0;intj =0; Getnext ();intSlen =strlen(S);intPlen =strlen(P); while(I<slen && J<plen) {if(j==-1||            S[i]==p[j]) {i++;        j + +; }Elsej = Next[j];if(j = = Plen)            {ans++;        j = Next[j]; }    }returnAns;}intMain () {intTscanf("%d", &t); while(t--) {ans =0;scanf("%s%s", p,s); KMP ();printf("%d\n", ans); }return 0;}

Below gives a tle code, is not feeling with the front almost the same, please look for the bug, in fact, this is also an experience ah, said more are tears ah ... ；

#include <iostream>#include <cstdio>#include <cstring>using namespace STD;Const intMAXN =1000005;CharS[MAXN], P[MAXN];intNEXT[MAXN];intans;voidGetnext () {intj =0;intK =-1; next[0] = -1; while(J <strlen(P)) {if(k==-1||            P[j]==p[k]) {k++;            j + +;        NEXT[J] = k; }Elsek = Next[k]; }return;}intKMP () {inti =0;intj =0; Getnext (); while(i<strlen(S) && j<strlen(P)) {if(j==-1||            S[i]==p[j]) {i++;        j + +; }Elsej = Next[j];if(J = =strlen(P)) {ans++;        j = Next[j]; }    }returnAns;}intMain () {intTscanf("%d", &t); while(t--) {ans =0;scanf("%s%s", p,s); KMP ();printf("%d\n", ans); }return 0;}

Unlike the previous is in the length of the calculation string, if it has been in the while loop, it will always count, will be tle, so directly in the outside forget, next time must pay attention, there should be no next time ...

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Poj 3461 Oulipo